Just try to think that there are three other empoyees and that they are not alone.
My H works with OW and I know they can't do anything but talk there and thats was bad enough. H says they hardly talk any more and only about work when nessesary but I still wonder once in a while. He has been doing pretty good though. I can't sit and worry about OW though she means nothing to me. I just try to make home a place that H will want and myself as desiable as I can.
Try to be the greener grass as it is said on here. Be upbeat and validate what he feels, it is important. BUT do not let him use you as a doormat(cake-eat) Set boundries for your self to help you cope. Walking out of the room and going to another to watch tv was a good move. You removed yourself from his crap. Remember it is about him not you.
Jak
You don't get to choose how you're going to die. Or when, you can only decide how you're going to live now. ~Joan Baez